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第六期
陈飞翔1,2,丁 沙1,2,水中和2,张国志1,郑俊杰2
摘 要:磷石膏矿渣基水泥是一种新型环保免烧型胶凝材料,采用45%的磷石膏、49%的矿渣、2%的钢渣和4%的硅酸水泥熟料经混合、粉磨而成。因目前磷石膏矿渣基水泥混凝土还没有明确的配合比设计方法,故采用三种常用的混凝土配合比设计方法对磷石膏矿渣基水泥混凝土的配合比进行设计和配制。结果表明,全计算法无论是胶凝材料用量还是砂率均在普通法和简易法之间,包裹程度较好,无漏石、泌水现象,较适用于C40磷石膏矿渣基水泥混凝土的配制。
Abstract: Phosphogypsum slag cement is a new kind of environmental un-burnt cementitious materials, which is mixed and ground with 45% phosphogypsum, 49% slag, 2% steel slag and 4% silicate cement clinker. There is no clear mix proportion design and preparation of phosphogypsum slag cement concrete, so design method to design and preparation of mix proportion for phosphogypsum slag cement concrete is carried out by three kinds of common concrete mix proportion. The results show that, overall calculation method for cementitious materials dosage and sand ratio is between common method and simple method, which is applied for proportion of C40 phosphogypsum slag cement concrete with good parcel level, non drain stone, and un-bleeding.
许 晴1,谭钦文1,辛保泉1,欧阳臣2,罗 洁1
摘 要:为了探究不同农作物秸秆对水泥基材料的性能影响,分别利用小麦、玉米、水稻三种常见农作物秸秆与水泥制备秸秆纤维-水泥复合材料,并从预处理方式、纤维掺量、纤维长度等方面考察三种复合材料的物理力学性能。试验结果表明:三种预处理方式中,热碱处理后秸秆中的半纤维素含量大量减少,明显减弱秸秆对水泥缓凝时间的影响;复合材料力学强度随着秸秆掺量的提高先增加后减小,并在掺量为2%时达到最佳力学强度,纤维长度的增加对力学强度不利;复合材料的干密度和吸水率在不同纤维掺量、长度条件下均呈反比;经预处理后,三种秸秆纤维-水泥复合材料物理力学性能均得到提高,三种秸秆作为水泥添加材料的优选顺序为:小麦>玉米>水稻。
Abstract: In order to explore the influence of different crop straw on properties of cement-based materials, straw fiber-cement composite materials are prepared by three kinds of crop straw (wheat, corn, rice) and cement, physical and mechanical properties of three kinds of composite materials are studied by pretreatment method, fiber dosage and fiber length. The results show that, the content of hemicellulose in straw is decreased after thermal alkaline treatment, and the influence of straw on the setting time of cement is obviously decreased, mechanical strength of composite material is increased first and then decreased with the increase of straw dosage, the best mechanical strength is achieved when straw dosage is 2%, the increase of fiber length is detrimental to mechanical strength; the dry density and water absorption of composite material is inversely proportional to different fiber dosage and length. After the pretreatment, the physical and mechanical properties of the three kinds of straw fiber-cement composite materials are improved, and the optimal order of three kinds of straw as the cement adding material is the wheat, corn and rice.
余成行,肖 鑫,谢光辉
摘 要:分析了复杂型钢组合结构内浇C70混凝土的特点和难点,按照优化的配合比进行生产和质量控制,对比分析多种施工工艺后采用导管导入法进行内浇混凝土施工,并在结构实体内预埋应变计等测试元件检测混凝土的硬化性能以评价结构浇筑质量。检测数据表明,所选择的混凝土配合比、施工浇筑工艺和质量控制过程能够满足结构质量控制要求。
Abstract: Characteristics and difficulties of complex steel composite structure cast in C70 concrete are analyzed, optimized mixing proportion for production and quality control are carried out. Cast concrete construction used by catheter introduction method is compared and analyzed after a variety of construction techniques, structure casting quality are evaluated by hardening properties of tested concrete which is embedded strain gauge in structural concrete. The monitoring data shows that, structure quality control requirements are satisfied by choosing mix proportion of concrete, construction cast technique, and quality control process.
刘航军1,曹振生1,刘宗志1,车建国1,李 能2,3
摘 要:对福州某工程顶管施工期间地表位移、土体位移及孔隙水压力进行了现场监测,并根据实测结果分析研究了顶管施工的土体扰动特性。结果表明,顶管施工引起的地表位移可分为顶管到达前沉降、施工扰动沉降、管土间隙沉降及土体固结沉降四个阶段;土体位移(相对地表)在顶管机头距离监测断面5m范围内达到最大,而孔隙水压力变化比土体位移变化要及时,可通过监测孔隙水压力对施工引起的土层移动作出超前预测。
Abstract: The site monitoring of surface displacement, soil displacement and pore water pressure in Fuzhou pipe-jacking construction is carried out, and properties of soil disturbance for pipe-jacking construction are studied and analyzed by measured data.The results show that, surface displacement caused by pipe-jacking construction can be divided into four stages, settlement before the arrival of pipe, settlement of pipe jacking construction disturbance, settlement of clearance between pipe and soil and settlement of soil consolidation. Soil displacement (relative to the surface) reached the maximum when the distance between pipe and monitoring cross section is 5m. Pore water pressure changes more timely than soil displacement, which soil displacement can be predicted by monitoring the pore water pressure.
王 政1,2,张敬书1,2,赵 俊2,3,刘 乐1,2,刘海兴1,2,张伟鹏1,2
摘 要:为了使承重型横孔连锁混凝土小型空心砌块用于村镇的砌体结构,需要测定该砌块的物理力学性能。本文根据相关规范的试验方法对该砌块进行了基本的物理力学性能试验。试验结果表明,密度、空心率、吸水率、相对含水率、干缩值、软化系数、抗冻性等均满足现行规范要求。承重型横孔连锁混凝土小型空心砌块的强度等级达MU10级,可以用于砌体结构的承重墙。
Abstract: In order to use load bearing horizontal-hole interlock concrete small hollow block in rural masonry structures, physical and mechanical properties of block are determined. According to relevant specification, basic physical and mechanical performance experiment of block is carried out in this paper. The experimental results show that, the proposed block can satisfy current specification of density, the hollow rate, water absorption, the relative water content, dry shrinkage, softening coefficient and frost resistance, and its strength reaches MU10 which may be used for masonry-structured load bearing walls.
龙文武1,2,王劲松1,卢 恺1
摘 要:通过微机控制电液伺服机(300kN)对150mm×150mm×300mm泡沫混凝土棱柱体进行了轴心单轴压缩试验,测得泡沫混凝土弹性模量、应力-应变本构关系等力学性能。在ABAQUS中建立与实验尺寸相同的泡沫混凝土棱柱体三维模型,并设置泡沫混凝土材料本构关系参数。对模型采用时间-位移的线性加载方法进行了单轴轴心压缩模拟,以验证ABAQUS中泡沫混凝土模型的正确性。通过对模型输出的荷载-时间曲线、荷载-位移曲线、应力-塑性应变曲线分析表明,设置的ABAQUS泡沫混凝土模型能较好地模拟泡沫混凝土轴心单轴压缩实验结果。
Abstract: The uniaxial compression test of 150mm×150mm×300mm foam concrete prism was carried out by using computer controlled servo machine (300kN), mechanical properties of elastic modulus of foam concrete and stress-strain constitutive relation were measured. A three dimensional model of foam concrete prism with the same size as experimental size was established in ABAQUS, and constitutive relation parameters of foam concrete were set up. In order to verify the correctness of the ABAQUS model, the model is simulated by uniaxial compression that using time-displacement linear loading method. By analyzing the model output load-time curve, load-displacement curve and stress-strain curve, uniaxial compression test of foam concrete can be simulated by the ABAQUS foam concrete model.